Helium is an example of what type of substance?

Helium is classified as an element because it is a pure substance that consists of only one type of atom. Elements are the simplest forms of matter that cannot be broken down into simpler substances through chemical reactions. Helium is found on the periodic table and is designated by the symbol "He." It is a noble gas and is characterized by its unique properties, such as being colorless, odorless, and non-reactive under most conditions. The distinction of helium as an element is important in chemistry and physics, as it is a fundamental building block of matter. In contrast, mixtures, compounds, and alloys involve combinations of different substances, either physically or chemically, which is not the case for helium.